It is well known that the effectiveness of a pump assembly is measured by the quality of its construction and its efficiency. The size of the assembly and its power with relation to its size are even more important where the assembly is disposed within confined area such as the back or base of a chair or seat.
Other vane pump assemblies have been produced for providing fluid to and from fluid receptacles. Among the assemblies in the art are those whose construction includes a pump housing, a pump motor disposed on one end of the pump housing and a cover positioned on the opposite end of the housing. Typically, such pumps further include a housing liner capsule positioned within the housing, a composite assembly disposed within the liner capsule, a stem which extends from the motor to receive and rotatably engage the composite assembly, and a housing cover. The housing is positioned on the motor about the stem. The composite assembly typically includes a hub having a centrally disposed pore for being positioned on the stem and a plurality of vanes which are evenly spaced and movably received in the hub. The pump housing cover typically includes an intake port and an outlet port. In operation, an electrical current causes the motor to rotate the stem and the composite assembly. As the composite assembly rotates each vane is variably extended from within the hub. The variable movement of the vanes in the hub create a force which draws fluid into the liner capsule through the intake port and urges that fluid out the outlet port and into the fluid receptacle.
Pump devices in the art require precision assembly to insure their effective operation. The pump housing cover is seated on the pump housing using mounting screws. When the mounting screws are not properly seated in the pump housing, the housing cover fails to seat properly on the pump housing and the composite assembly fails to generate air pressure sufficient to fill the fluid receptacle as quickly or completely as desired. Consequently, the need for precision assembly of pumps in the art increases the potential for malfunction due to mis-seating the housing cover. Moreover, the need for precision assembly adds to the overall costs of these pumps as each unit must be end-line tested to insure its operation. Each unit found to be malfunctioning as a result of this inspection must be repaired or rebuilt, as necessary.
Pump devices in the art are known to generate a high degree of heat during their operation due to the function of the motor and the high speed of rotation of the composite assembly in the pump housing. The heat generated by these pumps is even greater where they include a conventional motor which is designed to stall once it attains a maximum pre-selected pressure. The pump housing of pump assemblies in the art is typically fabricated from plastic to make the pump more lightweight and economical to produce. The high heat generated by operation of a pump causes expansion of the plastic pump housing. Continued operation of the pump ultimately results in a permanent distortion of the plastic housing and the operational failure of the pump. None of the pump devices in the art are adequately equipped to handle the effects of the high heat generated by their operation. Consequently, the vane pump assemblies of the art are of limited utility.
Pump devices in the art are also use specific. The maximum output of any vane pumping assembly in the art is regulated by the preselection of a motor having a maximum output designed to stall the pump at a preselected maximum pressure. Given this construct, a variation the fluid pressure provided by any pump in the art can only be obtained is by substitution of that pump assembly with another like pump assembly having a motor of another preselected maximum output. The cost to purchase identical pumps of differing maximum outputs, as well as that for the labor and materials for substituting these pumps has heretofore rendered such variations in maximal pump pressure expensive and impractical.
Therefore, it is an object of this invention to provide a vane pump assembly whose maximum output is regulated by a biasing means having a desired biasing force rather than by the maximum output of a preselected motor.
It is also an object of this invention to provide a vane pump having a biasing means which is accessible and interchangeable to accommodate the different pressure needs of the fluid device for which it is utilized.
Another object of this invention is to provide a vane pump assembly which is of compact construction such that it is discretely disposed in select structures, such as the seat back of vehicle seats, and is integrable into the seat support system.
A further object of this invention is to provide a vane pump which reduces the cost of manufacture and the need for repair by eliminating the need to precisely seat the cap member onto the pump housing.
Yet another object of this invention is to provide a vane pump assembly which eliminates pump failure due to over-inflation by permitting leakage of pressurized air from the pump housing when the pressure within the inner housing reaches a selected level.
It is an object of this invention to provide a vane pump which eliminates pump failure by permitting the motor and pump assembly to continue to rotate, and not stall, when a predetermined pressure is reached and excess pressure is vented from the assembly through the pump housing.
Moreover, it is an object of this invention to provide a vane pump assembly which is easily integrated into a seat support system which includes at least one bladder, at least one conduit and a switch for providing comprehensive comfort support to a seat occupant.